New types of spherical expansion compressors were disclosed in Chinese Patent No. ZL200610104569.8, entitled “ball-shape compressor capable of realizing multi-stage compression”, Chinese Patent No. ZL200620079799.9, entitled “CO2 spherical expansion compressor”, and Chinese Patent No. ZL200820028592.8, entitled “double-compressor opposed-type CO2 spherical expansion compressor”, which are advantageous over other known expansion compressors, such as compact structure, less parts, reliable sealing, powerful resistance to “liquid strike”, less vibration, and high efficiency, etc., and are widely used in refrigeration, air conditioning, and other related fields.
However, all the above are compressors of fixed volume ratios, which are not adapted to variable working, conditions. It was found in further studies that the above-mentioned spherical expansion compressors may be designed more optimally, making them improved in comprehensive capabilities, and at the same time, adapted to variable working conditions.